A double-cone collision point ignition heavy frequency laser fusion device and a target assembly functional metal material screening method thereof

Abstract

The application provides a double-cone collision ignition heavy frequency laser fusion device and a target assembly functional metal material screening method thereof. The double-cone collision ignition heavy frequency fusion device comprises a heavy frequency compression laser, a heavy frequency ignition laser, a compression cone, an ignition cone, a spherical cap target, a cone connecting piece, a fusion protection cover, a target chamber buffer gas and a fusion target ball. The pulsed heavy frequency laser and the high-speed moving fusion target assembly of the heavy frequency fusion device have good space-time matching characteristics, can work under single or heavy frequency fusion extreme conditions, and are suitable for frozen targets and normal temperature targets. The fusion target assembly functional metal material screening method is a rigorous material selection process from a basic physical property preliminary screening to impact dynamics and X-ray radiation key performance calibration, and finally through full physical coupling simulation verification. According to the material screening method, tungsten, lead, tantalum and gold and other heavy metals are determined as the preferred functional materials. The double-cone collision ignition heavy frequency fusion device has the characteristics of high fusion gain, strong radiation resistance, low radioactivity and low economic cost, and is suitable for heavy frequency laser fusion power generation and space propulsion and other applications.

Description

Technical Field

[0001] This invention relates to the fields of laser fusion and high energy density physics, and in particular to a method for screening functional metal materials for a biconical collision ignition high-repetition-rate laser fusion device and its target components. Background Technology

[0002] Biconical collision ignition (DCI) is a laser fusion ignition scheme distinct from traditional center ignition. This scheme first guides the implosion and collision of spherical cap materials through two compression cones, forming a high-density compressed plasma. Then, a picosecond laser interacts with the ignition cones to generate a high-current electron beam, heating the high-density fuel to ignition state, achieving high-efficiency ignition and high-gain fusion. This scheme significantly reduces the energy requirement of the driving laser and relaxes the implosion symmetry requirement, showing significant application potential in laser fusion energy.

[0003] However, previous research on biconical fusion ignition has mostly focused on single-shot fusion ignition and high-energy gain, with less research on biconical fusion ignition devices in repetitive fusion scenarios. For example, how to maintain the initial design state of the biconical fusion ignition cone and cap materials within the extremely complex fusion target sphere, how to protect the fusion target sphere from damage by the high-intensity fusion products of repetitive bursts, and how to achieve good spatiotemporal matching between pulsed repetitive lasers and high-speed moving fusion target components within the fusion target sphere all require novel fusion devices to address.

[0004] Furthermore, the selection of functional metal materials for fusion target components is crucial. Not only do they need to provide sufficient inertial confinement, but their interaction with the radiation field also indirectly affects implosion performance and ignition success. Currently, gold is widely used as the cone material in this field, mainly due to its high density, good machinability, and experience in traditional inertial fusion schemes. However, gold is a precious metal, resulting in high costs. There is an urgent need to establish a standardized and systematically verifiable material screening method to obtain functional metal materials for fusion target components that offer better or comparable overall performance to gold in high-repetition-rate laser fusion scenarios. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for screening functional metal materials for a biconical collision ignition repetitive laser fusion device and its target components, in order to solve the problems in the prior art where single-shot biconical collision ignition targets are difficult to maintain their initial design state in repetitive fusion, traditional vacuum fusion target spheres face serious damage risks in repetitive fusion, single-shot fusion does not consider the dynamic spatiotemporal matching characteristics of the driving laser and the fusion target, and there is a lack of a method for screening functional metal materials for fusion target components adapted to repetitive fusion.

[0006] To achieve the above and other related objectives, the present invention provides a double-cone collision ignition high-repetition-rate laser fusion device, the device comprising a high-repetition-rate laser, a fusion target assembly, a target chamber buffer gas, and a fusion target sphere; the high-repetition-rate laser comprises at least two sets of high-repetition-rate compression lasers and one set of high-repetition-rate ignition lasers; the fusion target assembly comprises two compression cones, at least one ignition cone, a spherical cap target disposed within the compression cone, a cone connector, and a fusion protection shield; the two compression cones are coaxial and their apexes face each other, the axis of the ignition cone is perpendicular to the axes of the two compression cones, the cone connector connects and fixes the compression cone and the ignition cone within the fusion protection shield, the fusion target sphere encloses the fusion protection shield, the high-repetition-rate compression laser penetrates the fusion target sphere and the fusion protection shield to irradiate the spherical cap target of the compression cone, the high-repetition-rate ignition laser penetrates the fusion target sphere and the fusion protection shield to irradiate the bottom of the ignition cone, and the target chamber buffer gas fills the space between the fusion protection shield and the fusion target sphere.

[0007] This invention also provides a method for screening functional metal materials for target components of the aforementioned biconical collider ignition high-repetition-rate laser fusion device, characterized by comprising the following steps: S1. Initial screening: Based on the average atomic number Z, average density ρ, and the radioactivity of fusion products after irradiation, a preliminary set of candidate materials is obtained. S2. Inertial confinement capability verification: For the preliminary candidate material set, calculate its equation of state based on first principles, evaluate its impact compressibility and impact resistance under high pressure, and screen out a subset A of materials with dynamic performance comparable to or better than gold. S3. Radiation Characteristics Verification: For the materials in material subset A, perform the following operations: Calculate its radiation opacity, determine its laser-to-M-band hard X-ray radiation conversion rate, and screen for lasers that satisfy the laser-to-M-band hard X-ray radiation conversion rate η. M-band ≤ 20%, M-band hard X-ray peak energy E M-band The material subset B required to be ≤ 3.0 keV; S4. Full Physical System Verification: For the materials in material subset B, a fully coupled radiation fluid simulation of laser-loaded double cone implosion is performed using a radiation hydrodynamic program to evaluate their comprehensive performance in the complete double cone collision ignition process. S5. Material Determination: Based on the above verification results, the target material is determined.

[0008] As described above, the biconical collision ignition high-repetition-rate laser fusion device and its target component functional metal material screening method of the present invention have the following beneficial effects: In the biconical collision ignition high-repetition-rate laser fusion device of this invention, the fusion protection shield can not only isolate the environmental radiation inside the fusion target sphere (i.e., the target chamber) and maintain the fusion target components and fusion fuel in a preset state, but also rely on its own inertia to buffer the high-intensity instantaneous impact generated by fusion, thus protecting the fusion target sphere. The fusion target sphere is filled with inert gas as a buffer gas, which can further extend the fusion energy release time to the microsecond level and control the instantaneous peak thermal power on the target sphere surface to be below 1000 MW / cm². 2 The entire device automatically completes the entire process of target delivery, laser target ablation, fusion energy release, and fusion product discharge at a frequency greater than 0.01 Hz, achieving continuous and stable fusion power output. Utilizing selected non-precious metal low-radiation fusion target components made of functional metal materials, the device significantly reduces the generation of harmful X-rays in the M-band, significantly decreases the content of high-Z impurities in the fuel, and exhibits superior compression efficiency and ignition stability compared to traditional gold cone devices, while also substantially reducing the cost of target material preparation.

[0009] The target component functional metal material screening method of this invention proposes a triple physical constraint that must be met simultaneously: "high Z, high density, and low harmful radiation". This lays a theoretical foundation for material selection in laser fusion and similar extreme environments, and provides a complete material selection verification process from microscopic property calculation to macroscopic system simulation, ensuring the reliability of the conclusions and having universal guiding significance.

[0010] The target component functional metal material screening method of this invention explicitly excludes the composite design path of "using mid-Z materials as radiation modulation functional layers" (such as gold cone chromium plating); although such materials have "soft" radiation spectra, their radiation easily leads to harmful pre-ablation expansion of the fuel shell, ultimately impairing implosion compression. This step of "excluding unfavorable materials" enhances the scientific rigor and reliability of the target component functional metal material screening method of this invention. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the double-cone collision ignition high-frequency laser fusion device of the present invention.

[0012] Figure 2 This is a schematic flowchart of the target component functional metal material screening method of the present invention.

[0013] Figure 3 Figure 3(a) shows the two-dimensional simulation obtained in Example 2; Figure 3(b) shows the initial outline of the cone; Figure 3(b) shows the comparison between fuel zone density and high Z impurity distribution, with the tungsten cone scheme on the left and the gold cone scheme on the right.

[0014] Explanation of icon numbers 1. High-repetition-rate laser 2 Fusion Target Components 3. Target chamber buffer gas 4 Fusion Target Spheres 1-1 High-Repetition Compressed Laser 1-2 Repetition Rate Ignition Laser 2-1 Compression Cone 2-2 Ignition Cone 2-3 Spherical Crown Target 2-4 Conical connector 2-5 Fusion Protective Shield 4-1 Target Repetition Rate Window 2-31 Ablation layer 2-32 Fusion Fuel Detailed Implementation

[0015] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0016] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0017] In this invention, the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0018] Furthermore, it should be understood that the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, does not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. It should also be understood that the combined connection relationship between one or more devices / apparatus mentioned in this invention does not preclude the existence of other devices / apparatus before or after the combined devices / apparatus, or the insertion of other devices / apparatus between these explicitly mentioned devices / apparatus, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or limiting the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0019] The first aspect of this invention provides a double-cone collision ignition high-repetition-rate laser fusion device, the device comprising a high-repetition-rate laser 1, a fusion target assembly 2, a target chamber buffer gas 3, and a fusion target sphere 4; the high-repetition-rate laser 1 comprises at least two sets of high-repetition-rate compression lasers 1-1 and one set of high-repetition-rate ignition lasers 1-2; the fusion target assembly 2 comprises two compression cones 2-1, at least one ignition cone 2-2, a spherical cap target 2-3 disposed within the compression cone, a cone connector 2-4, and a fusion protection shield 2-5; the two compression cones 2-1 are coaxial and their apexes face each other, and the ignition cone 2-2... The axis is perpendicular to the axis of the two compression cones 2-1. The cone connector 2-4 connects and fixes the compression cone 2-1 and the ignition cone 2-2 inside the fusion protection shield 2-5. The fusion target sphere 4 encloses the fusion protection shield 2-5. The high-repetition-rate compression laser 1-1 penetrates the fusion target sphere 4 and the fusion protection shield 2-5 to irradiate the spherical cap target 2-3 of the compression cone. The high-repetition-rate ignition laser 1-2 penetrates the fusion target sphere 4 and the fusion protection shield 2-5 to irradiate the bottom of the ignition cone 2-2. The target chamber buffer gas 3 fills the space between the fusion protection shield 2-5 and the fusion target sphere 4.

[0020] In this invention, the cone connector also serves as an important shielding component to prevent the repetitive compression laser, the ablation plasma of the spherical cap target, and X-rays from damaging the clean environment of the heated gold cone, thus providing a favorable short-density standard-length plasma environment for the main pulse of the subsequent repetitive heating laser to generate fast electrons with moderate energy.

[0021] In this invention, the pulsed high-repetition-rate laser 1 and the high-speed moving fusion target assembly 2 have good dynamic spatiotemporal matching characteristics within the fusion target sphere 4.

[0022] In some embodiments of the present invention, the high-repetition-rate compressed laser 1-1 is a nanosecond laser with a center wavelength less than 1100 nm; preferably, the center wavelength of the nanosecond laser is 343 nm or 351 nm, each group of high-repetition-rate compressed lasers 1-1 includes at least 4 nanosecond lasers, the wavelength difference between the center wavelengths of each nanosecond laser does not exceed 50 nm, and the pulse width of each nanosecond laser is greater than 3 ns. The peak light intensity of the nanosecond lasers after being superimposed on the surface of the spherical cap target is greater than 10 TW / cm². 2 Laser aiming error ≤ 50μm.

[0023] In some embodiments of the present invention, the repetitive firing laser 1-2 is a picosecond laser, wherein there is at least one picosecond laser, the total energy of all lasers is greater than or equal to 1 kJ, and the peak laser intensity is greater than 1 x 10⁻⁶ kJ. 18 W / cm 2 Each picosecond laser pulse width is not less than 1 ps. In a more preferred embodiment of the present invention, the total energy of the picosecond laser is ≥1 kJ, the pulse width is >1 ps, and the peak intensity is ≥1 x 10⁻⁶. 18 W / cm 2 Aiming error ≤ 30μm.

[0024] In this invention, the timing synchronization accuracy of the high-repetition-rate compression laser 1-1, the high-repetition-rate ignition laser 1-2, and the fusion target assembly reaching the center of the fusion target sphere 4 is better than 100 μs.

[0025] In some embodiments of the present invention, the spherical cap target 2-3 in the fusion target assembly 2 is suitable for both room temperature target and cryogenic freezing target working conditions.

[0026] In a preferred embodiment of the present invention, the spherical cap target 2-3 includes an ablation layer 2-31 and fusion fuel 2-32; when the repetitive laser 1 irradiates the fusion target assembly 2, the fusion energy released by a single shot of the fusion fuel 2-32 is not less than 0.2 MJ, the fusion energy gain is not less than 20, the fusion repetition frequency is not less than 0.01 Hz, and the average fusion power is not less than 0.1 MW.

[0027] In a more preferred embodiment of the present invention, the fusion fuel 2-32 is cryogenic deuterium-tritium fuel when used in cryogenic target conditions. Preferably, the cryogenic fuel is a solid deuterium-tritium ice fuel filled in carbon foam or a liquid deuterium-tritium fuel.

[0028] In a more preferred embodiment of the present invention, the fusion fuel 2-32 is a metal deuterium-tritium compound fuel suitable for use under ambient temperature target conditions. Preferably, the metal deuterium-tritium compound fuel is encapsulated in an ablation layer. More preferably, the metal deuterium-tritium compound fuel is selected from one or more of beryllium deuterium-tritium (BeDT), lithium deuterium-tritium (Li2DT), and lithium boron deuterium-tritium (LiBD2T2).

[0029] In a more preferred embodiment of the present invention, the ablation layer 2-31 is made of carbon-containing plastic or diamond film; preferably, the ablation layer 2-31 is made of carbon-deuterium plastic and / or hydrocarbon plastic.

[0030] In some embodiments of the present invention, the functional metal material on the fusion target assembly 2 is a high atomic number, low-emissivity metal material, wherein the high atomic number is Z>50, the low emissivity is a laser-to-M-band hard X-ray radiation conversion rate of less than 20%, and the M-band hard X-ray peak energy E M-band ≤ 3.0 keV; preferably, the functional metal material is one or more of gold (Au), tungsten (W), lead (Pb) and tantalum (Ta).

[0031] In some embodiments of the present invention, the materials of the compression cone 2-1 and the ignition cone 2-2 are functional metal materials, or metal cone composite materials containing functional metal materials; preferably, the functional metal material is one or more of gold (Au), tungsten (W), lead (Pb), and tantalum (Ta); preferably, the metal cone composite material is a functional metal material with a hydrocarbon or carbon-deuterium plastic coated on its inner surface; preferably, the thickness of the functional metal material of the compression cone 2-1 is not less than 5 μm; preferably, the thickness of the functional metal material of the ignition cone 2-2 is not less than 2 μm. More preferably, the thickness of the functional metal material of the compression cone 2-1 is 10~50 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, or 50 μm. More preferably, the thickness of the functional metal material of the ignition cone 2-2 is 10~30 μm, for example, 10 μm, 20 μm, or 30 μm.

[0032] In some embodiments of the present invention, the material of the conical connector 2-4 is a composite of a matrix material and a functional metal material; preferably, the matrix material is a hydrocarbon plastic; preferably, the functional metal material is one or more of gold (Au), tungsten (W), lead (Pb), and tantalum (Ta); preferably, the thickness of the functional metal material of the conical connector 2-4 is not less than 2 μm. More preferably, the thickness of the functional metal material of the conical connector 2-4 is 10~30 μm, for example, 10 μm, 20 μm, or 30 μm.

[0033] In some embodiments of the present invention, the fusion protective shield 2-5 is made of a composite of a matrix material and a functional metal material; preferably, the matrix material is a hydrocarbon plastic, low-activation stainless steel or copper; preferably, the functional metal material is one or more of gold (Au), tungsten (W), lead (Pb) and tantalum (Ta).

[0034] In some embodiments of the present invention, the fusion protection shield 2-5 is a vacuum-sealed cavity, and the vacuum-sealed cavity is provided with at least three laser incident windows, corresponding to two sets of high-repetition-rate compression lasers 1-1 and at least one set of high-repetition-rate ignition lasers 1-2, respectively; preferably, the vacuum-sealed cavity is a cylindrical cavity or a spherical cavity; preferably, the material of the laser incident window is a light-transmitting material, such as polyimide. The laser incident window has good laser transmittance. The vacuum-sealed cavity has good airtightness and mechanical strength.

[0035] In some embodiments of the present invention, the target chamber buffer gas 3 is one or more inert gases, and the electron number density of the target chamber buffer gas 3 is less than the critical electron number density corresponding to the wavelengths of the high-repetition-rate compression laser 1-1 and the high-repetition-rate ignition laser 1-2; preferably, the target chamber buffer gas 3 is argon, xenon, or an argon-xenon mixture; preferably, the electron number density of the target chamber buffer gas 3 is 1 x 10⁻⁶. 20 pcs / cm 3 .

[0036] In some embodiments of the present invention, the fusion target sphere 4 is further provided with a repetition rate delivery window 4-1, and the fusion target assembly 2 is adapted to enter the fusion target sphere 4 from the repetition rate delivery window 4-1.

[0037] In a preferred embodiment of the present invention, the frequency repetition rate delivery window 4-1 is located on the equatorial plane or the north pole of the fusion target sphere 4, and a residual target recovery module is provided opposite the frequency repetition rate delivery window 4-1.

[0038] In some embodiments of the present invention, the various structures of the fusion device have good spatiotemporal matching characteristics. When the fusion target assembly 2 moves at high speed to the center of the fusion target sphere 4 at a frequency of not less than 0.01 Hz, the high-repetition-rate compression laser 1-1 hits the cap target 2-3 with an aiming error better than 50 micrometers, and the high-repetition-rate ignition laser 1-2 hits the bottom of the ignition cone 2-2 with an aiming error better than 30 micrometers. If the fusion target assembly 2 incident through the high-repetition-rate target delivery window 4-1 of the fusion target sphere 4 is not hit by the high-repetition-rate laser 1, it will be captured by the residual target recovery module on the fusion target sphere 4. It will not hit the high-repetition-rate laser 1 incident window on the fusion target sphere 4.

[0039] A second aspect of the present invention provides a method for screening functional metal materials for target components of a biconical collider ignition high-repetition-rate laser fusion device as described above, characterized by comprising the following steps: S1. Initial screening: Based on the average atomic number Z, average density ρ, and the radioactivity of fusion products after irradiation, a preliminary set of candidate materials is obtained. S2. Inertial confinement capability verification: For the preliminary candidate material set, calculate its equation of state based on first principles, evaluate its impact compressibility and impact resistance under high pressure, and screen out a subset A of materials with dynamic performance comparable to or better than gold. S3. Radiation Characteristics Verification: For the materials in material subset A, perform the following operations: Calculate its radiation opacity, determine its laser-to-M-band hard X-ray radiation conversion rate, and screen for lasers that satisfy the laser-to-M-band hard X-ray radiation conversion rate η. M-band ≤ 20%, M-band hard X-ray peak energy E M-band The material subset B required to be ≤ 3.0 keV; S4. Full Physical System Verification: For the materials in material subset B, a fully coupled radiation fluid simulation of laser-loaded double cone implosion is performed using a radiation hydrodynamic program to evaluate their comprehensive performance in the complete double cone collision ignition process. S5. Material Determination: Based on the above verification results, the target material is determined.

[0040] In some embodiments of the present invention, in step S1, the average atomic number Z ≥ 50 and the average density ρ ≥ 10.0 g / cm³. 3 Fusion products do not produce long-lived radioactive elements after irradiation.

[0041] In some embodiments of the present invention, in step S2, the kinetic performance being comparable to that of gold means that under pressures higher than 10... 4 At GPa, the single impact compression ratio of the material is less than that of gold, or the relative difference between the two is less than 20%.

[0042] In some embodiments of the present invention, step S3, the radiation characteristic verification specifically includes: a) Calculate its typical temperature at >500 eV and >0.1 g / cm³. 3 Radiative opacity in density states; b) The laser-to-M-band hard X-ray radiative conversion efficiency η was determined through laser-plasma interaction simulation. M-band The M-band hard X-rays refer to X-rays with energies of 2-4 keV; c) Filter out those that satisfy η M-band ≤ 15%, M-band hard X-ray peak energy E M-band Material subset B with a value ≤ 3.0 keV.

[0043] In some embodiments of the present invention, in step S4, the evaluation index for overall performance includes at least the final areal density of the fuel shell ≥ 0.3 g / cm³. 2 And the integrity of the cone structure.

[0044] In some embodiments of the present invention, the functional metal material of the fusion target assembly 2 includes the functional metal material of the compression cone 2-1, the ignition cone 2-2, the cone connector 2-4, and the fusion protective shield 2-5.

[0045] The present invention will be further described in detail below with reference to specific embodiments and comparative examples. The described embodiments are only for explaining the present invention and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the equipment used in the following embodiments is conventional equipment in the art; unless otherwise specified, the reagents used are commercially available products or prepared by conventional methods in the art. Items not described in detail in the following embodiments can be achieved using conventional experimental methods in the art.

[0046] Example 1: A 500kJ laser-driven biconical collision ignition repetitive frequency fusion device like Figure 1 As shown, this embodiment is a DCI biconical collision ignition high-repetition-rate fusion device with a total driving laser of 500kJ and an operating repetition rate of 1Hz. The core structure includes a high-repetition-rate laser 1, a fusion target assembly 2, a target chamber buffer gas 3, and a fusion target sphere 4. These structures work together to achieve high-frequency cyclic operation of fuel compression, rapid ignition, and fusion energy release. Based on the core concept of biconical collision ignition, the device decouples the physical processes of fuel compression and ignition heating. A single 1Hz target firing cycle is divided into four major working stages, each of which relies on corresponding hardware structures to complete a precise workflow.

[0047] (1) Fusion target assembly in place This stage is accomplished using the high-repetition-rate, high-speed target delivery mechanism of the fusion target assembly 2 and the fusion target sphere 4. The fusion target assembly 2 includes a compression cone 2-1, an ignition cone 2-2, a spherical target 2-3, a cone connector 2-4, and a fusion protection shield 2-5. The fusion protection shield 2-5 can shield the materials of the compression cone 2-1, the ignition cone 2-2, and the spherical target 2-3 from the negative impact of the matter and radiation field inside the fusion target sphere 4 on the materials before the laser arrives, maintaining the vacuum environment inside the fusion target assembly 2. For cryogenic targets, it can maintain the fuel in a cryogenic state, and for ambient temperature targets, it can prevent the fuel from prematurely vaporizing. The high-repetition-rate target delivery mechanism of the device can precisely adapt to the 1Hz operating frequency, stably delivering the fusion target assembly 2 (with a radius of approximately 1 cm) from the high-repetition-rate target delivery window 4-1 of the fusion target sphere 4 to the center of the fusion target sphere with a diameter of 10 m.

[0048] (2) Nanosecond laser irradiation of compressed fuel This stage involves fuel compression using a high-repetition-rate nanosecond compressed laser in conjunction with the fusion target assembly. The total energy of the nanosecond compressed laser is approximately 450 kJ, the laser wavelength is 351 nm, and the peak intensity is approximately 500 TW / cm². 2With a pulse width of approximately 10 ns and an aiming error better than 50 μm, it can drive the spherical cap target 2-3 to implode spherically symmetrically. The outer layer of the spherical cap target 2-3 structure embedded in the compression cone 2-1 (tungsten cone) is an ablation layer, and the interior is filled with deuterium-tritium fusion fuel. After laser irradiation, the ablation material forms plasma, which drives the internal deuterium-tritium fuel to accelerate inward at high speed. The inner radius of the spherical cap target is 1400 μm, the thickness of the deuterium-tritium fuel is 130 μm, and the thickness of the hydrocarbon ablation layer is 40 μm. The compression cone 2-1, with its high atomic number and high density, forms an effective inertial confinement, constraining the fuel to converge towards the center of the device along the axis. The X-ray conversion rate of the M-band (2~4 keV) of the tungsten material is only 8%, which can effectively suppress the pre-ablation problem of the cone wall, reduce the mixing of high Z impurities into the fuel, and ensure the purity of fuel compression. Two compressed and accelerated fuel plasmas are ejected at high speed from the compression cone and collide in the central region of the device, forming a high-density plasma cloud and achieving efficient compression.

[0049] (3) Picosecond laser injection for fast ignition When the fuel compression collisions reach peak density, ultrafast ignition is achieved using a picosecond laser with a high repetition rate. The picosecond laser has a total energy of 50 kJ, a pulse width of 10 ps, ​​and a peak intensity ≥ 1 x 10⁻⁶. 18 W / cm 2 With an aiming error better than 5μm, the picosecond laser is precisely incident on the bottom of the ignition cone 2-2 at the preset timing node. The ultra-high power laser interacts with the metal material of the ignition cone 2-1 (tungsten cone) to generate a directional high-energy fast electron beam. The fast electrons quickly penetrate and penetrate deep into the central high-density fuel region, raising the low-temperature high-density fuel to the fusion critical temperature within a picosecond timescale, successfully triggering the deuterium-tritium fusion ignition.

[0050] (4) Self-sustaining fusion energy release After successful fuel ignition, self-sustaining fusion combustion occurs, with the energy gain of the fusion target exceeding 30. The instantaneous energy release from fusion relies on the interaction between the fusion target assembly 2 and the target chamber buffer gas 3 with the X-rays, neutrons, and charged particles generated by fusion, achieving time broadening and peak intensity reduction. The original 100 ps instantaneous energy release time is broadened to 4 μs, ensuring that the peak heat flux density, peak impact pressure, and peak neutron concentration reaching the first wall of the fusion target sphere 4 are below the safety threshold of the fusion target sphere 4 material. The preferred target chamber buffer gas 3 is an inert gas such as argon, which is not easily ignited or exploded and does not undergo chemical reactions, facilitating the subsequent extraction of unburned fusion fuel from the buffer gas discharged from the target chamber. Furthermore, combined with a large-size fusion target sphere structure with a diameter of 10 m, the peak thermal power of the first wall of the fusion target sphere is controlled at 1000 MW / cm². 2Following the completion of a single fusion reaction, the vacuum system on the fusion target sphere 4 automatically expels the plasma from the sphere. The external target delivery mechanism then precisely delivers the fusion target assembly 2 to the center of the target sphere at a frequency of 1 Hz. The device continuously completes the entire process of target delivery, compression, ignition, and energy release at a repetitive frequency of 1 Hz. The pulsed fusion energy release is converted into a long-term, stable, continuous fusion energy output through the nuclear power conversion system outside the fusion target sphere 4.

[0051] Example 2: A method for screening cone materials, taking a tungsten cone as an example. This embodiment uses a tungsten cone as an example, employing the functional metal material screening method of the present invention, such as... Figure 2 As shown, a preferred cone material suitable for bicone collision ignition is obtained.

[0052] 1. Step S1: Initial screening Tungsten has an atomic number Z=74>50 and a density ρ=19.3 g / cm³. 3 >10.0 g / cm 3 It does not produce long-lived radioactive elements after irradiation with fusion products such as neutrons and protons, and passes the initial screening.

[0053] 2. Step S2: Verification of inertial constraint capability The equation of state for tungsten was calculated using the FEOS program. Figure 3 (a) shows the calculated single-impact compression curves of tungsten and gold. As shown in the figure, at pressures exceeding 10... 4 In the DCI-related high-pressure region at GPa, the two curves essentially overlap. Further analysis shows that in this range, the compressibility of tungsten is lower than that of gold, with a difference of less than 8%. Meanwhile, Figure 3 (b) shows that under the corresponding impact pressure, the impact resistance of tungsten is greater than that of gold, with a difference of less than 3%. Conclusion: The inertial confinement capacity of tungsten is completely equivalent to that of gold.

[0054] 3. Step S3: Verification of radiation characteristics a) Theoretical calculations: Opacity was calculated using a matter parameter program (such as SNOP). Under typical coronal conditions, the M-band radiation peak intensity of tungsten is significantly lower than that of gold, and the peak energy of X-rays decreases by 2.2 keV from 2.6 keV in gold, shifting towards lower energies by approximately 400 eV.

[0055] b) Laser-driven simulation: A planar target is irradiated with lasers of varying intensities. The typical laser intensity in DCI is 400 TW / cm². 2 The conversion rate η from tungsten laser to M-band hard X-rays was measured using simulation. M-band ≈ 8%; while the corresponding value for gold is ~13%. Tungsten's η M-band The preferred standard is ≤20%.

[0056] Conclusion: Tungsten has excellent radiation characteristics of "low harmfulness".

[0057] 4. Step S4: Full System Performance Verification Two-dimensional cylindrical coordinate full implosion simulation was performed using a radiation fluid program. Figure 3 The performance of gold and tungsten cones was compared under the same DCI target parameters. The results showed: A) Structural integrity: Both cones remained intact without breakage. B) High Z-mixing: The gold ion mass fraction in the central collision region of the gold cone was approximately 5%, while the tungsten ion mass fraction in the corresponding region of the tungsten cone was less than 0.1%. C) Fuel compression: The fuel areal density obtained by the tungsten cone scheme was approximately 15% higher than that of the gold cone scheme.

[0058] 5. Step S5: Material Determination Based on the verification results of all the above steps, tungsten performed excellently in all tests and passed the system verification, and was therefore determined to be the preferred material for the double-cone ignition cone.

[0059] It should be noted that the method described in this embodiment is not limited to obtaining tungsten as a material, but rather provides a standardized implementation process for solving material screening problems under such extreme environments. Any material screening and design based on the same physical principles and following or equivalent to this verification process falls within the protection scope of this invention.

[0060] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. For example, the total laser energy may be 1000 MJ or other energies, and the operating mode may be single-shot mode, 10Hz repetition rate mode, or other modes. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A biconical collision ignition high-repetition-rate laser fusion device, characterized in that, The device includes a high-repetition-rate laser (1), a fusion target assembly (2), a target chamber buffer gas (3), and a fusion target sphere (4); the high-repetition-rate laser (1) includes at least two sets of high-repetition-rate compression lasers (1-1) and one set of high-repetition-rate ignition lasers (1-2); the fusion target assembly (2) includes two compression cones (2-1), at least one ignition cone (2-2), a spherical cap target (2-3) disposed within the compression cone, a cone connector (2-4), and a fusion protection shield (2-5); the two compression cones (2-1) are coaxial and their apexes face each other, and the axis of the ignition cone (2-2) is perpendicular to the two compression cones (2-1). The axis of the cone is connected by the cone connector (2-4), which connects and fixes the compression cone (2-1) and the ignition cone (2-2) inside the fusion protection shield (2-5); the fusion target sphere (4) encloses the fusion protection shield (2-5); the high-repetition-rate compression laser (1-1) penetrates the fusion target sphere (4) and the fusion protection shield (2-5) to irradiate the spherical cap target (2-3) of the compression cone, and the high-repetition-rate ignition laser (1-2) penetrates the fusion target sphere (4) and the fusion protection shield (2-5) to irradiate the bottom of the ignition cone (2-2); the target chamber buffer gas (3) is filled between the fusion protection shield (2-5) and the fusion target sphere (4).

2. The biconical collision ignition high-repetition-rate laser fusion device according to claim 1, characterized in that, The repetition rate compressed laser (1-1) is a nanosecond laser with a center wavelength of less than 1100 nm; preferably, the center wavelength of the nanosecond laser is 343 nm or 351 nm, each group of repetition rate compressed lasers (1-1) includes at least 4 nanosecond lasers, the wavelength difference between the center wavelengths of each nanosecond laser does not exceed 50 nm, and the pulse width of each nanosecond laser is greater than 3 ns.

3. The biconical collision ignition high-repetition-rate laser fusion device according to claim 1, characterized in that, The repetitive firing lasers (1-2) are picosecond lasers, each with at least one path, a total energy of at least 1 kJ, and a peak laser intensity greater than 1 x 10⁻⁶. 18 W / cm 2 Each picosecond laser pulse width is no less than 1 ps.

4. The biconical collision ignition high-repetition-rate laser fusion device according to claim 1, characterized in that, The spherical cap target (2-3) in the fusion target assembly (2) is suitable for both room temperature target and cryogenic freezing target working conditions.

5. The biconical collision ignition high-repetition-rate laser fusion device according to claim 4, characterized in that, The spherical target (2-3) includes an ablation layer (2-31) and fusion fuel (2-32); when the repetitive laser (1) irradiates the fusion target assembly (2), the fusion energy released by the fusion fuel (2-32) in a single shot is not less than 0.2 MJ, the fusion energy gain is not less than 20, the fusion repetition frequency is not less than 0.01 Hz, and the average fusion power is not less than 0.1 MW.

6. The biconical collision ignition high-repetition-rate laser fusion device according to claim 5, characterized in that, The fusion fuel (2-32) is cryogenic deuterium-tritium fuel when used in cryogenic target conditions; preferably, the cryogenic fuel is solid deuterium-tritium ice fuel filled in carbon foam or liquid deuterium-tritium fuel.

7. The biconical collision ignition high-repetition-rate laser fusion device according to claim 5, characterized in that, The fusion fuel (2-32) is a metal deuterium-tritium compound fuel suitable for use in ambient temperature target conditions. Preferably, the metal deuterium-tritium compound fuel is encapsulated in an ablation layer.

8. The biconical collision ignition high-repetition-rate laser fusion device according to claim 5, characterized in that, The ablation layer (2-31) is made of carbon-containing plastic or diamond film; preferably, the ablation layer (2-31) is made of carbon-deuterium plastic and / or hydrocarbon plastic.

9. The biconical collision ignition high-repetition-rate laser fusion device according to claim 7, characterized in that, The metal deuterium-tritium compound fuel is one or more of beryllium deuterium-tritium, lithium deuterium-tritium, and lithium boron deuterium-tritium.

10. The biconical collision ignition high-repetition-rate laser fusion device according to claim 1, characterized in that, The fusion target assembly (2) has a functional metal material, which is a metal material with a high atomic number and low M-band hard X-ray radiation. The high atomic number is Z>50, and the low radiation means that the laser-to-M-band hard X-ray radiation conversion rate is less than 20%. The peak energy E of the M-band hard X-ray is... M-band ≤ 3.0 keV; preferably, the functional metal material is one or more of gold, tungsten, lead and tantalum.

11. The biconical collision ignition high-repetition-rate laser fusion device according to claim 1, characterized in that, The compression cone (2-1) and ignition cone (2-2) are made of functional metal materials or metal cone composite materials containing functional metal materials; preferably, the functional metal materials are one or more of gold, tungsten, lead and tantalum; preferably, the metal cone composite materials are functional metal materials with hydrocarbon or carbon-deuterium plastics coated on the inner surface; preferably, the thickness of the functional metal material of the compression cone (2-1) is not less than 5 μm; preferably, the thickness of the functional metal material of the ignition cone (2-2) is not less than 2 μm.

12. The biconical collision ignition high-repetition-rate laser fusion device according to claim 1, characterized in that, The material of the conical connector (2-4) is a composite of a matrix material and a functional metal material; preferably, the matrix material is a hydrocarbon plastic; preferably, the functional metal material is one or more of gold, tungsten, lead and tantalum; preferably, the thickness of the functional metal material of the conical connector (2-4) is not less than 2 μm.

13. The biconical collision ignition high-repetition-rate laser fusion device according to claim 1, characterized in that, The fusion protective shield (2-5) is made of a composite of a matrix material and a functional metal material; preferably, the matrix material is a hydrocarbon plastic, low-activation stainless steel or copper; preferably, the functional metal material is one or more of gold, tungsten, lead and tantalum.

14. The biconical collision ignition high-repetition-rate laser fusion device according to claim 1, characterized in that, The fusion protection shield (2-5) is a vacuum-sealed cavity, and the vacuum-sealed cavity is provided with at least three laser incident windows, which correspond to two sets of high-repetition-rate compression lasers (1-1) and at least one set of high-repetition-rate ignition lasers (1-2), respectively; preferably, the vacuum-sealed cavity is a cylindrical cavity or a spherical cavity; preferably, the material of the laser incident window is a light-transmitting material.

15. The biconical collision ignition high-repetition-rate laser fusion device according to claim 1, characterized in that, The target chamber buffer gas (3) is one or more inert gases, and the electron number density of the target chamber buffer gas (3) is less than the critical electron number density corresponding to the wavelengths of the high-repetition-rate compression laser (1-1) and the high-repetition-rate ignition laser (1-2); preferably, the target chamber buffer gas (3) is argon, xenon, or an argon-xenon mixture; preferably, the electron number density of the target chamber buffer gas (3) is 1×10⁻⁶. 20 pcs / cm 3 .

16. The biconical collision ignition high-repetition-rate laser fusion device according to claim 1, characterized in that, The fusion target sphere (4) is also provided with a repetition rate delivery window (4-1), and the fusion target assembly (2) is adapted to enter the fusion target sphere (4) from the repetition rate delivery window (4-1).

17. The biconical collision ignition high-repetition-rate laser fusion device according to claim 16, characterized in that, The frequency repetition rate target delivery window (4-1) is located on the equatorial plane or the north pole of the fusion target sphere (4), and a residual target recovery module is provided opposite the frequency repetition rate target delivery window (4-1).

18. A biconical collision ignition high-repetition-rate laser fusion device as described in any one of claims 1 to 17, characterized in that, The various structures of the fusion device have good spatiotemporal matching characteristics. When the fusion target assembly (2) moves at a high speed at a frequency of not less than 0.01Hz to the center of the fusion target sphere (4), the high-repetition compression laser (1-1) hits the spherical cap target (2-3) with an aiming error of better than 50 micrometers, and the high-repetition ignition laser (1-2) hits the bottom of the ignition cone (2-2) with an aiming error of better than 30 micrometers. If the fusion target assembly (2) is not hit by the high-repetition laser (1) when it enters from the high-repetition target delivery window (4-1) of the fusion target sphere (4), it will be captured by the residual target recovery module on the fusion target sphere (4).

19. A method for screening functional metallic materials for target components of a biconical colliding ignition high-repetition-rate laser fusion device according to any one of claims 1 to 18, characterized in that, Includes the following steps: S1. Initial screening: Based on the average atomic number Z, average density ρ, and the radioactivity of fusion products after irradiation, a preliminary set of candidate materials is obtained. S2. Inertial confinement capability verification: For the preliminary candidate material set, calculate its equation of state based on first principles, evaluate its impact compressibility and impact resistance under high pressure, and screen out a subset A of materials with dynamic performance comparable to or better than gold. S3. Radiation Characteristics Verification: For the materials in material subset A, perform the following operations: Calculate its radiation opacity, determine its laser-to-M-band hard X-ray radiation conversion rate, and screen for lasers that satisfy the laser-to-M-band hard X-ray radiation conversion rate η. M-band ≤ 20%, M-band hard X-ray peak energy E M-band The material subset B required to be ≤ 3.0 keV; S4. Full Physical System Verification: For the materials in material subset B, a fully coupled radiation fluid simulation of laser-loaded double cone implosion is performed using a radiation hydrodynamic program to evaluate their comprehensive performance in the complete double cone collision ignition process. S5. Material Determination: Based on the above verification results, the target material is determined.

20. The method for screening functional metal materials for target components according to claim 19, characterized in that, It also includes one or more of the following features: 11) In step S1, the average atomic number Z ≥ 50 and the average density ρ ≥ 10.0 g / cm³. 3 Fusion products do not produce long-lived radioactive elements after irradiation. 21) In step S2, the kinetic performance being comparable to that of gold means that under pressures higher than 10... 4 At GPa, the material's single-impact compression ratio is less than that of gold, or the relative difference between the two is less than 20%. 31) In step S3, the radiation characteristic verification specifically includes: a) calculating its typical temperature at >500 eV and >0.1 g / cm³. 3 a) Radiation opacity under density conditions; b) Radiative conversion efficiency η from laser to M-band hard X-rays determined by laser-plasma interaction simulation. M-band The M-band hard X-rays refer to X-rays with energies of 2-4 keV; Filter out those that satisfy η M-band ≤ 20%, M-band hard X-ray peak energy E M-band Material subset B with a voltage ≤ 3.0 keV; 41) In step S4, the comprehensive performance evaluation index shall at least include the final areal density of the fuel shell ≥ 0.3 g / cm³. 2 And the integrity of the cone structure.

21. The method for screening functional metal materials for target components according to claim 19, characterized in that, The functional metal materials of the fusion target assembly (2) include the functional metal materials of the compression cone (2-1), the ignition cone (2-2), the cone connector (2-4), and the fusion protective shield (2-5).

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